While the Colorado Rapids defender can rightfully draw satisfaction from his burgeoning career, there's a scope to the beautiful game that can't be understated. Think you're ahead of the curve? Perhaps here. But don't forget there's a world of talent out there to stack up against.

O'Neill learned that much when he traveled to Turkey for the U-20 World Cup in June. In his first start for the Americans, he found himself keeping tabs on budding Juventus star Paul Pogba of France. And in his second match, O'Neill was face-to-face with Pogba's club teammate, Richmond Boakye of Ghana.

"I just realized it's a big game out there," said O'Neill, who turned 20 earlier this month. "I'm playing in MLS, starting however many games, but there's always players out there that are starting games for Juventus that are the same age as me. You've just got to keep working and keep staying focused to try and match them."

In American soccer circles, however, O'Neill is already turning heads for his swift integration into the heart of an MLS back line.

Considering center back is a slot often reserved for finely tuned veterans, coach Oscar Pareja's trust is noteworthy. Factor in that O'Neill is a natural midfielder and the development is all the more telling.

"When you watch him play center back right now, you would never guess he really hasn't been playing it," said Rapids captain Drew Moor, O'Neill's partner in central defense. "The fact that he's transitioned into a center back in his first season as a professional, at 19 years old when he started, I think it speaks volumes for his work ethic and his dedication to the game."

After spurning a scholarship from the University of Virginia to sign with the Rapids as an academy product in June 2012, O'Neill played in one match last year before taking advantage of early injuries and suspensions to seize his starting spot this season.

A 6-foot-2 player with a silky touch, O'Neill knows he still has plenty to learn about the position. Like how to better compete aerially. Step into the attack. Track forwards' runs.

Yet O'Neill never doubted his ability to contribute promptly with the Rapids. Examining Colorado's 10-2-8 mark in matches he's started, it would appear his confidence was justified.

"I definitely thought there was a good chance for me trying to push for a spot in the team," O'Neill said. "I'm a competitor. I wanted to be on the field as quick as I could."

It turns out O'Neill's competitive instincts are a family trait. His father Colm was a noted Gaelic football player, and his brother Darragh punts for the University of Colorado football team.

Moving stateside from Ireland when Shane was 1 year old, the O'Neills spent time in The Woodlands, Texas, before putting down roots in Boulder, Colo., in 2002. Although O'Neill has represented the USA on the youth level, he retains eligibility to play for Ireland and has had informal contact with that federation.

So would he listen if his native country's national team came calling?

"I'd definitely be open to anything at this stage," O’Neill said. "I mean, my whole family is from Ireland, I was born there, so there's still some Irish pride in me. If I got the opportunity, I'd have to look seriously into it. But obviously playing for the U.S. has done really good things for me also."

In the short term, O'Neill is concentrating on getting the Rapids through the tight Western Conference playoff hunt and into the postseason.

Even though Moor said his youthful teammate can be a "goofball" in the locker room, O'Neill is "more mature than he leads people on to believe." Looking past the levity, Moor sees passion. Focus. Ambition.

It's the approach of a 20-year-old who has already tested himself against world-class talent — and found himself eager for the next challenge.

"He has a great fighting spirit, wants to win every game," Moor said. "He's a good kid, he's a competitive kid. I think the future is extremely bright with Shane."